Keira Knightley had to get permission from her mother to buy her most expensive item of clothing.

The Millionaire actress owns a sheepskin coat from fashion house Burberry, which cost £2,795, but she could only go through with the purchase after being given the go-ahead by her mum Sharman MacDonald - who told her she had to wear the garment every day.

She told Britain's Elle magazine: "My mum was like, 'You cannot spend that amount of money on a coat,' and I was like, 'No, you're right I can't, I can't'. And then literally it was months and months of thinking about it and thinking, 'I'm not going to do it, I'm not going to do it.'

"But then she said, 'Right, if you're going to buy it, you have to wear it all the time.'

"I wore it every day last year and I'm going to wear it every day this year".

Keira - who got her first big break on the big screen in 2001 movie 'The Hole' when she was just 16 - has long been careful with her finances, and in 2009 she revealed the global recession had made her stop buying expensive designer shoes and start renting them instead.

Keira, now 25, explained: "I think when I was very young and I suddenly started earning a bit of money and I could actually afford to buy shoes, I got very excited and bought a lot. I mean a lot!

"I haven't bought any in quite a while. Now I just rent them for the day. They give them to me for the day and I give them back in the evening, which is good."